Three dimensional topography measuring has been applied in fields such as industrial detection, preservation of cultural relics, geographical mapping, architectural modeling, reverse engineering, medical plastic, film animation, somatosensory entertainment, virtual reality, and three dimensional printing, wherein is as an important three dimensional measurement method, active light stereoscopic vision has been massively applied in scientific researches and commercial instruments because of its features including quick measurement, simple structure and high precision, and a basic flow includes that: Step 1: a coordinate relation of a left camera and a right camera is marked; Step 2: structural lights are projected onto a surface of a measured object, so as to form a characteristic texture; Step 3: the left camera and the right camera acquire an image respectively so as to obtain a left view and a right view; Step 4: matching points corresponding to each other in the left view and the right view are matched, and the parallax is calculated; Step 5: calculation is performed according to the parallax and the coordinate relation between the left and right cameras, so as to obtain a three dimensional point cloud of the measured object.